This invention relates to an auxiliary structure and arrangement for an in-line multi-cylinder internal combustion engine, and more particularly to a structural arrangement wherein the auxiliaries of the engine, such as the auxiliaries of a fuel injection system, are disposed in close proximity to the engine so as to provide a compact and effective arrangement.
The advantages of providing internal combustion engines with direct cylinder fuel injection are well recognized. Such direct injection has the advantage of insuring more accurate control of the fuel supply and a better control of the exhaust gas emissions from such engines. In-cylinder fuel injection has been used instead of carburetion to mix the fuel in four-cycle engines, whereas in two-cycle crankcase compression engines, direct fuel injectors have been employed along with a carburetor system. When employed together, the injectors supply fuel directly to the combustion chambers, while the carburetor system supplies a fuel/air mixture to the crankcase chambers which may also serve to cool the pistons under high speed running conditions.
The in-cylinder fuel injection system typically includes an injector device that atomizes the fuel and supplies it along with the compressed air to the combustion chambers of the cylinders. This type of fuel injection system has also been equipped with various auxiliary components such as a compressor for supplying compressed air to the fuel/air injector as well as a high pressure fuel pump and pressure regulator for supplying pressure regulated fuel to the fuel/air injector. A generator, driven by the engine crankshaft is also provided for producing the electrical energy to operate to the system. Although this type of fuel injection system is very effective in controlling and metering the fuel supply to the engine, it can present a problem as to space depending on its application. This is particularly true in outboard motors where it is desireable to limit the amount of space occupied by the engine and its associated components so that the outboard motor, and in particular the power head wherein the engine is contained, can be made compact.
It is therefore desireable in outboard motors to position the auxiliary components of a fuel injection system in close proximity to the engine to reduce the amount of parts needed and to provide a more compact power head. To this end, it has been proposed in connection with an outboard motor incorporating a V-type internal combustion engine to position the auxiliaries in the valley of the V and to position the air compressor and generator close to one another with a common driving shaft. See Japanese Unexamined Patent Publication Hei2-141392. By positioning the auxiliary components in the valley between the cylinders, these components may be located relatively close to the engine without increasing the outer dimensions of the power head.
However, there still remains a problem of how to position the larger auxiliaries, such as the compressor and the generator, relative to an in-line engine which has no valley, so as to minimize the space required for the engine and its auxiliary components. There has also been a problem with respect to the positioning of the high pressure fuel system auxiliaries, such as the high pressure pump, with respect to an in-line engine so as to provide a compact and effective arrangement.
It is, therefore, a principal object of this invention to provide an auxiliary system for an in-line multi-cylinder internal combustion engine which includes a plurality of auxiliary units, one positioned in close proximity to the engine on the side opposite the engine exhaust ports and the other positioned in close proximity to a corner of the engine to minimize the space required for the engine and its associated components.
It is another object of this invention to provide an improved structural arrangement for an in-line multi-cylinder internal combustion engine which employs direct cylinder injection, wherein the auxiliaries of the fuel injection system are disposed in close proximity to the engine to provide a compact and effective arrangement.